The present invention relates to an image projecting device for projecting an image on a screen, and capable of shifting the image projected on the screen in a direction parallel to the screen.
As an example of such an image projecting device, in Japanese Patent Provisional Publication HEI 5-27324, an image projecting device employing a liquid crystal device is described. In the image projecting device described in the publication, parallel light is emitted by a light source and passes through a transmission type liquid crystal panel. The liquid crystal panel is driven to modulate the beam transmitting therein. The light beam passed through and modulated by the liquid crystal panel is projected on a screen via a condenser lens and an image projecting lens.
The condenser lens and the image projecting lens are mounted on a lens shift mechanism so as to be unitarily movable in a direction perpendicular to an optical axis of the image projecting lens. By shifting the condenser lens and the image projecting lens in the direction perpendicular to the optical axis, the image projected on the screen is shifted in the direction parallel to the screen without the keystone distortion.
Generally, various members of the image projecting device are accommodated in a casing, while the image projecting lens is arranged to be protruded from the casing. When the image projecting device is carried, such a protruded part may be inadvertently used in the manner of a handle, i.e., that the weight of the projector may be inappropriately supported on the protruding lens. If the projecting lens is made shiftable as described in the publication, when the protruded part of the image projecting lens is grasped and the image projecting device is lifted or carried to change a location of the image projecting device, undesirable force may be applied to the lens shifting mechanism and the mechanism may be broken.
Further, in the conventional structure of the image projecting device, a relatively large opening should be formed on the casing where the projecting lens is protruded in order to allow the projecting lens to move in the direction perpendicular to its optical axis. Therefore, a space is formed between the outer circumference of the projecting lens and the inner circumference of the opening, which deteriorates the appearance of the image projecting device.